Centos 7システム最適化

Centos 7カーネル最適化
SELINUXの無効化

# grep -i ^selinux /etc/selinux/config
SELINUX=enforcing
SELINUXTYPE=targeted 

最大プロセス数と最大ファイルオープン数の変更
ulimit-nと-uはLinuxの最大プロセス数と最大ファイルオープン数を表示できます
ファイルの最後に追加

cat >> /etc/security/limits.conf << EOF
\* soft nofile 1024000
\* hard nofile 1024000
\* soft nproc  1024000
\* hard nproc  1024000  
EOF

説明:'*'は、すべてのユーザーに対してnoprocが最大プロセス数を表すnofileが最大ファイルオープン数を表す
/etc/security/limitsを変更する必要があります.d下のconfファイル(前の構成情報を上書きします)、私のは20-nprocです.conf

cat /etc/security/limits.d/20-nproc.conf
# Default limit for number of user's processes to prevent
# accidental fork bombs.
# See rhbz #432903 for reasoning.

\*          soft    nproc     4096
root       soft    nproc     unlimited

次のように変更します.

cat /etc/security/limits.d/20-nproc.conf
# Default limit for number of user's processes to prevent
# accidental fork bombs.
# See rhbz #432903 for reasoning.

\* soft nproc  1024000
\* hard nproc  1024000 

カーネル最適化
vi/etc/sysctl.d/99.sysctl.conf

#  ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

#       
net.ipv4.icmp_echo_ignore_broadcasts = 1

#     icmp      
net.ipv4.icmp_ignore_bogus_error_responses = 1

#      
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0

#        
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1

#        
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0

#  sysrq  
kernel.sysrq = 0

#core      pid     
kernel.core_uses_pid = 1

#   SYN      
net.ipv4.tcp_syncookies = 1

#        
kernel.msgmnb = 65536
kernel.msgmax = 65536

#           bytes
kernel.shmmax = 68719476736
kernel.shmall = 4294967296

#timewait   ，  180000
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096        87380   4194304
net.ipv4.tcp_wmem = 4096        16384   4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216

#                           ，               
net.core.netdev_max_backlog = 262144

#            DoS   
net.ipv4.tcp_max_orphans = 3276800

#                   
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0

#            SYNACK     
net.ipv4.tcp_synack_retries = 1

#            SYN     
net.ipv4.tcp_syn_retries = 2

#  timewait     
net.ipv4.tcp_tw_recycle = 1

#    。   TIME-WAIT sockets       TCP   
net.ipv4.tcp_tw_reuse = 1

net.ipv4.tcp_mem = 94500000 915000000 927000000

net.ipv4.tcp_fin_timeout = 1

# keepalive      ，TCP   keepalive      。   2   

net.ipv4.tcp_keepalive_time = 30

#           
net.ipv4.ip_local_port_range = 1024    65000

#        ，  65536
#net.netfilter.nf_conntrack_max=655350
#net.netfilter.nf_conntrack_tcp_timeout_established=1200

#           
net.ipv4.conf.all.accept_redirects = 0

net.ipv4.conf.default.accept_redirects = 0

net.ipv4.conf.all.secure_redirects = 0

net.ipv4.conf.default.secure_redirects = 0

vm.max_map_count=655360